1. Field of the Invention
The present invention is generally related to vehicle suspension assemblies. More particularly, the present invention is related to a front suspension fork for use on an off-road bicycle.
2. Description of the Related Art
Suspension fork assemblies are often utilized on off-road bicycles, or mountain bikes, to absorb energy imparted to the front wheel by the terrain on which the bicycle is being ridden. The use of a suspension fork allows a rider to traverse rougher terrain, at a greater speed and with less fatigue in comparison to riding a bicycle equipped with a rigid fork. Due to the fact that bicycle riders vary greatly in both weight and riding ability, it is highly desirable that certain performance aspects of the suspension fork, such as compression and rebound damping characteristics, be capable of adjustment to suit a particular individual.
To avoid the need to disassemble the fork in order to adjust the suspension settings, it is preferable to locate the adjustment controls such that they are externally accessible. Furthermore, an individual rider is likely to ride in wide variety of terrain conditions, often during the course of a single ride or race. Accordingly, adjustment of the damping characteristics while riding is greatly facilitated by locating the adjustment controls on an upper portion of the suspension fork.
Ideally, the adjustment controls would be disposed on a damper cap assembly at the top of one of the fork legs and include a compression lock-out for substantially preventing compression of the fork. The compression lock-out feature is desirable so that the suspension fork may selectively behave substantially as a rigid fork while riding on smooth terrain, to enhance both handling and power transfer to the rear wheel of the bicycle. However, prior art mountain bike suspension forks have failed to provide both a compression lock-out feature and external damping adjustment controls that are easily accessible while riding. Further, existing mechanisms for providing external damping adjustment and compression lock-out require undue complexity. Thus, an improved mountain bike suspension fork is desirable.
Preferred embodiments of the present suspension fork include a damping assembly having a damping control assembly located at an upper portion of the fork. A hollow shaft connects a piston to the control assembly. On compression of the fork, damping fluid flows upward through the central passage of the shaft to the damping control assembly. With such a fluid flow arrangement, a simplified arrangement of externally accessible controls may be disposed on the control assembly. This arrangement permits compression damping, rebound damping and compression lock-out controls to be collectively located so as to be accessible to a rider of a bicycle, while the bicycle is being ridden.
In addition, a reservoir is preferably disposed in a lower portion of the fork such that fluid exiting the damping control assembly travels in a downward direction due to gravity, substantially the entire length of the fork. This arrangement advantageously allows the damping fluid to also lubricate certain internal components of the fork, including bushings, seals and a suspension coil spring, if provided.
A preferred embodiment comprises a bicycle front fork including an upper tube having a top portion, a bottom portion and an intermediate portion. A lower tube having a top portion, a bottom portion and an intermediate portion is telescopingly movable with respect to the upper tube. An upper control assembly is positioned at the top portion of the upper tube. A damping cartridge is positioned at least partly within the lower tube and defines a top portion, a bottom portion and an intermediate portion. At least a section of the lower tube surrounding the cartridge, at least partially defines a reservoir. A shaft extends from the top portion of the upper tube into the damping cartridge. A main damping piston is connected to the shaft and positioned in the cartridge. At least the bottom portion of the cartridge defines a lower internal chamber located below the piston. The piston, the shaft and the control assembly cooperate to define a flow channel from the chamber through the piston, the shaft and the control assembly to the reservoir.
A preferred embodiment comprises a bicycle front fork including an upper tube having a top portion, a bottom portion and an intermediate portion. A lower tube having a top portion, a bottom portion and an intermediate portion is telescopingly movable with respect to the upper tube. An upper control assembly is positioned at the top portion of the upper tube. A damping cartridge is positioned at least partly within the lower tube and defines a top portion, a bottom portion and an intermediate portion. At least a section of the lower tube surrounding the cartridge, at least partially defines a reservoir. The bottom portion of the damping cartridge defines a lower control assembly which operates to permit fluid to enter the cartridge from the reservoir through the lower control assembly, but prevents fluid from exiting the cartridge at low pressure levels. A shaft extends from the top portion of the upper tube into the damping cartridge. A main damping piston is connected to the shaft and positioned in the cartridge. At least the bottom portion of the cartridge defines a lower internal chamber located below the piston. The piston, the shaft and the control assembly cooperate to define a flow channel from the chamber through the piston, the shaft and the control assembly to the reservoir. The upper control assembly includes a one-way valve which prevents the flow of fluid from the reservoir through the control assembly when the shaft and the piston move upward away from the bottom portion of the damping cartridge.
A preferred embodiment comprises a bicycle front fork including an upper tube having a top portion, a bottom portion and an intermediate portion. A lower tube having a top portion, a bottom portion and an intermediate portion is telescopingly movable with respect to the upper tube. An upper control assembly is positioned at the top portion of the upper tube. A damping cartridge is positioned at least partly within the lower tube and defines a top portion, a bottom portion and an intermediate portion. At least a section of the lower tube surrounding the cartridge, at least partially defines a reservoir. A shaft extends from the top portion of the upper tube into the damping cartridge. A main damping piston is connected to the shaft and positioned in the cartridge. At least the bottom portion of the cartridge defines a lower internal chamber located below the piston. The piston, the shaft and the control assembly cooperate to define a flow channel from the chamber through the piston, the shaft and the control assembly to the reservoir. The upper control assembly also includes a lock-out valve which selectively prevents the flow of fluid from the shaft through the assembly and to the reservoir.
A preferred embodiment comprises a bicycle front fork including an upper tube having a top portion, a bottom portion and an intermediate portion. A lower tube having a top portion, a bottom portion and an intermediate portion is telescopingly movable with respect to the upper tube. An upper control assembly is positioned at the top portion of the upper tube. A damping cartridge is positioned at least partly within the lower tube and defines a top portion, a bottom portion and an intermediate portion. At least a section of the lower tube surrounding the cartridge, at least partially defines a reservoir. A shaft extends from the top portion of the upper tube into the damping cartridge. A main damping piston is connected to the shaft and positioned in the cartridge. At least the bottom portion of the cartridge defines a lower internal chamber located below the piston. The piston, the shaft and the control assembly cooperate to define a flow channel from the chamber through the piston, the shaft and the control assembly to the reservoir. A blow-off valve is positioned at the bottom portion of the cartridge to permit flow through the blow-off valve and into the reservoir in response to a threshold blow-off pressure.
A preferred embodiment comprises a bicycle front fork including an upper tube having a top portion, a bottom portion and an intermediate portion. A lower tube having a top portion, a bottom portion and an intermediate portion is telescopingly movable with respect to the upper tube. A shaft extends axially from the top portion of the upper tube. A main damping piston is connected to the shaft and at least partially defines a damping chamber. The fork defines a low speed compression circuit and a rebound circuit. A control assembly located at the top portion of the upper tube includes a first control connected to the low speed compression circuit and is manually adjustable, external of the fork. In a first position, fluid is able to flow through the low speed compression circuit and, in a second position, flow through said low speed compression circuit is prevented. A second control is connected to the rebound circuit and is manually adjustable, from external of the fork. In a first position, a first rate of flow through the rebound circuit is permitted and, in a second position, a second rate of flow through the rebound circuit is permitted. The first rate of flow is higher than said second rate of flow. The control assembly also comprises a third control connected to a restrictor, which communicates with the low speed compression circuit. The restrictor is manually movable from external of the fork between at least a first position, wherein the restrictor provides at least a first amount of resistance to flow through the low speed compression circuit, and a second position, wherein the restrictor provides a second amount of resistance to flow through the low speed compression circuit.
A preferred embodiment comprises a bicycle front fork including an upper tube having a top portion, a bottom portion and an intermediate portion. A lower tube having a top portion, a bottom portion and an intermediate portion is telescopingly movable with respect to the upper tube. A shaft extends axially from the top portion of the upper tube. A main damping piston is connected to the shaft and at least partially defines a damping chamber. The fork defines a low speed compression circuit. A control assembly located at the top portion of the upper tube includes a first control connected to the low speed compression circuit and is manually adjustable, external of the fork. In a first position, fluid is able to flow through the low speed compression circuit and, in a second position, flow through said low speed compression circuit is prevented. The control assembly also comprises a second control connected to a restrictor, which communicates with the low speed compression circuit. The restrictor is manually movable from external of the fork between at least a first position, wherein the restrictor provides at least a first amount of resistance to flow through the low speed compression circuit, and a second position, wherein the restrictor provides a second amount of resistance to flow through the low speed compression circuit.
A preferred embodiment comprises a shock absorber including an upper tube having a top portion, a bottom portion and an intermediate portion. A lower tube having a top portion, a bottom portion and an intermediate portion is telescopingly movable with respect to the upper tube. An upper control assembly is positioned at the top portion of the upper tube. A damping cartridge is positioned at least partly within the lower tube and defines a top portion, a bottom portion and an intermediate portion. At least a section of the lower tube surrounding the cartridge, at least partially defines a reservoir. A shaft extends from the top portion of the upper tube into the damping cartridge. A main damping piston is connected to the shaft and positioned in the cartridge. At least the bottom portion of the cartridge defines a lower internal chamber located below the piston. The piston, the shaft and the control assembly cooperate to define a flow channel from the chamber through the piston, the shaft and the control assembly to the reservoir.
A preferred embodiment comprises a bicycle having a front fork. The front fork includes an upper tube having a top portion, a bottom portion and an intermediate portion. A lower tube having a top portion, a bottom portion and an intermediate portion is telescopingly movable with respect to the upper tube. An upper control assembly is positioned at the top portion of the upper tube. A damping cartridge is positioned at least partly within the lower tube and defines a top portion, a bottom portion and an intermediate portion. At least a section of the lower tube surrounding the cartridge, at least partially, defines a reservoir. A shaft extends from the top portion of the upper tube into the damping cartridge. A main damping piston is connected to the shaft and positioned in the cartridge. At least the bottom portion of the cartridge defines a lower internal chamber located below the piston. The piston, the shaft and the control assembly cooperate to define a flow channel from the chamber through the piston, the shaft and the control assembly to the reservoir.